C++ vector::rend() Function

The C++ vector::rend() function returns a reverse iterator pointing to the vector's element that is preceding the first element (reversed past-the-last element). When increased, a reverse iterator moves to the beginning of the vector container and iterates in the opposite manner.

Similar to increasing an iterator, reducing a reverse iterator causes the vector container to move to the end. The function returns a const_reverse_iterator if the vector object is const-qualified. If not, a reverse iterator is returned. The time complexity of the rend() function is constant.

Syntax

Following is the syntax for C++ vector::rend() Function −

reverse_iterator rend() noexcept;
const_reverse_iterator rend() const noexcept;

Parameters

It doesn't accept any kind of parameter.

Example 1

Let's consider the following example, where we are going to use reserve() function.

#include <iostream>  
#include<vector>  
using namespace std;
  
int main(){  
   vector<int> tutorial{11,22,33,44};  
   vector<int>::reverse_iterator x;  
   for(x=tutorial.rbegin();x!=tutorial.rend();x++)  
      std::cout<< *x<<" ";  
   return 0;  
}  

Output

When we compile and run the above program, this will produce the following result −

44 33 22 11

Example 2

Considering the another scenario, where we are going to take string type and applying the rend() function.

#include <iostream>  
#include<vector>  
using namespace std;
  
int main() {  
   vector<string> course{"HTML","SQL","JS","OS"};  
   vector<string>::reverse_iterator x;  
   vector<string>::iterator a;  
   std::cout<<"before using rend():";  
   for(a=course.begin();a!=course.end();a++)  
      cout<<*a<<", ";  
   cout<<'\n';  
   cout<<"after using rend():";  
   for(x=course.rbegin();x!=course.rend();x++)  
      cout<<*x<<", ";  
   return 0;  
}

Output

On running the above program, it will produce the following result −

before using rend():HTML, SQL, JS, OS, 
after using rend():OS, JS, SQL, HTML,

Example 3

In the following example, we are going to use the push_back() function to insert the elements and applying the rend() function.

#include <iostream>  
#include<vector>  
using namespace std;

int main(){
   vector<string> car;
   car.push_back("RS7");
   car.push_back("Q6");
   car.push_back("GLS340D");
   car.push_back("CHERON");
   cout << "\nResult:\n";
   for (auto x = car.rbegin(); x != car.rend(); x++)
      cout << *x << " ";
   return 0;
} 

Output

When we execute the above program, it will produce the following result −

Result:
CHERON GLS340D Q6 RS7